Backpacks have for some time been very popular with children and young adults for carrying books and other articles to school or recreational activities. Recently, it has been increasingly common for older adults to use backpacks in place of large handbags or briefcases. The user of a backpack often has occasion to carry a backpack by hand. Accordingly, most backpacks have a carrying handle, which is usually a length of webbing that is attached at its ends to the upper end of the back of the backpack body and forms a loop that is large enough to be grasped. A handle in the form of a webbing loop tends to pinch the sides of the user's hand and can quickly become uncomfortable. Frequently, the user finds it more comfortable to use one of the shoulder straps as a carrying handle. Using a shoulder strap as a carrying handle allows the backpack body to hang down low to the ground, sometimes far enough down so that the shoulder strap that is not being grasped or even the body of the backpack touches the ground.
Another aspect of the construction of a backpack is the manner by which the straps are supported comfortably on the tops of the user's shoulders. Care must be taken in the design of the backpack to have the portions of the shoulder straps that rest on the shoulders stay in place and not slip off to the sides. At the same time, the straps should not tend to pull toward each other at the back of the user's neck. The positions of the portions of the shoulder straps that rest on the tops of the user's shoulders is largely governed by the spacing between the upper ends of the straps where they are attached to the body of the backpack. For any given spacing of the upper ends of the shoulder straps, the positions of the portions of the straps that rest on the user's shoulders varies somewhat, depending on the height at which the body of the backpack is carried on the user's back. If the body is carried high up on the user's back, the shoulder straps tend to pinch the back of the user's neck. If the body is carried low on the user's back, the shoulder straps can slip off to the laterally outer sides of the shoulders and may be uncomfortable to the user.